Last Update: January, 2010. Several months ago I added ghost shrimp. The crayfish leaves them alone but will eat any that die. A few weeks ago I added snails (from a trusted source to try to avoid disease). They are happily cleaning the algae and one even cleaned the crayfish. Previous crayfish I have had liked to eat these. Either this one is well fed or not that bright. Lazy?
If you are in the Fort Walton Beach, Florida area, Animal Kingdom sells these crayfish. There was a HUGE one in there when I was in last. Over twice the size of my guy. Probably a very mature female. 4 years old? more? Wish I knew. Petland sells them too but I have had Ick infestations from them too many times to recommend. At least this one. I do not know if all are this way, to be fair.
If you are looking for the knitted crayfish please click here otherwise read on for live crayfish keeping.
For many reasons I have a love for crustaceans. I find their behavior fascinating. Unfortunately if you are not set up for salt-water, you are limited on what are available. (Hmm…that reminds me, I will have to add a blog on crabs later.) Crayfish (crawfish, crawdads, mudbugs, freshwater lobsters, blue lobsters….) are usually thought of something you would eat (at least around here) but they are actually quite fun to watch. They have attitude.
I have kept “regular red” crayfish before and enjoyed them very much. Recently I came across a sale on blue crayfish. I have been wanting one of these beauties for some time so I snatched one up. The reds do not cost much, if anything, depending on where you get them. The blues are often bred to become more blue than what you would see in the wild so they can be more pricey. The blue coloring is natural and they can be found wild in South Florida and probably other areas as well. There are blue variations in other species of crayfish as well, but these guys are a nice, solid blue. Personality is the same as a red. You can also find all white crayfish, but they are harder to find. I like the blue.
I have not found much information on the web about keeping these guys. I will summarize some of what I found here and give the source links at the end. This applies to both the regular and the blue crayfish.
Lifespan: There is much disagreement on how long they live but it seems to be agreed that they do live at least 2 years and maybe up to 5 or 7 years. I do not yet know if there is a difference in lifespan for the males vs. females.
Feeding: They eat about anything. Best to have more veggies than meat in their diet. They are omnivores but should have plants before anything. Too much protein will cause molting problems. I use pellets for crabs, algae wafers for plecos, fresh peas, and sinking krill pellets at the moment. I have read that giving them clean egg shells also help build their exoskeleton but I have not tried this yet. A bit of fresh shrimp thrown in sometimes is a real treat. They LOVE snails and fish as well. Be careful if you provide snails, they can be carrying disease. I have lost one of mine this way. But if you find a good source, such as a clean pet shop (no ick) trying to get rid of “pest” snails in their planted tanks (often free) then give them a try. They go after them with gusto. They look like they are digging into a candy jar. They can eat a lot. One site said they eat their own body weight in 3 days. I just put in a little bit each night or skip days on feeding to avoid waste. Remove uneaten food. They will eat until they cannot fit anymore. I just overfed mine recently and he is walking around with food sticking out of his mouth and holding more food in one of his small pincers, waiting to be able to stuff it in. The dork.
A few sites said they will not eat fish. THEY WILL EAT YOUR FISH. Fast fish may have a chance but they are still vulnerable at night when the crayfish is most active. When the fish is sleeping, the crayfish can easily snag the fish. The crayfish are also fast enough to snag a swimming fish. I have seen this. One of the links I am providing has a picture for proof so do not listen to anyone saying they will not eat your fish. Even well fed crayfish will go for it. They are pigs. If you still wish to have fish, try those that prefer to stay at the top, even when sleeping.
What about big fish? Well, the tables may get turned. Big fish like to eat these guys sometimes.
Note – 1 US gallon = 3.79 liters. I keep meaning to convert throughout the text in these posts and hope to do so soon. But here is the formula for those who need it in the mean time. :) Hope it helps.
Housing: Crayfish will try to eat about anything they get their claws onto. I recommend keeping just one crayfish per 10 gallon tank. They will kill the other crayfish when given the chance and they will eat your fish (see feeding above). Tiny crayfish can be kept in smaller tanks. I have raised young ones in a large jar packed with plants for oxygen. If you can get small ones, go for it. It is great watching them grow. But eventually they do need to get to a larger tank. One of the reasons is that they put out a lot of waste. They need the filtration and frequent water changes. It is also suggested to add iodine to the water at one drop per 10 gallons per week. This is supposed to help with molting. I have tried this for about a month and I have had a successful molt within that time. Whether it was due to the iodine or to something else, I do not know. But I will continue with that tiny drop of iodine once a week since he is doing well….so far. (Note: I have been using iodine for around 6 months now (March, ’09). He has had 3 good molts so far!)
They can climb the filtration tube and escape. You will need to come up with a way (mesh?) to cover the openings in the back or have an internal filter. I keep my water level a little lower than I would for my fish (2-3 inches below rim). This keeps the lip of the aquarium and other bits out of reach. So far it works. The water will be noisy pouring in from the filter this way but it beats finding out that your crayfish has turned into a cat toy because he got out. (An old newbie mistake a few years ago-lucky that one lived-minus a few limbs that grew back later.) And yes, they need to stay in the water. They can be out of water as long as their gills stay wet, but only for short periods. They eventually get the wrong amount of oxygen and their body will dry out.
NOTE: I have been keeping the water level low, as stated above, for over a month 6 months and he has not escaped. This seems to work very well. The only routes of escape now are the filter tube and air tube. If he should manage to climb those above the water level, there is yet another lip to get past. This was a very easy way to do it without having to seal the tank. It may depend on your crayfish. This one does not seem determined to get out.
They also like something to hide in and climb on. They will dig in the gravel if the rocks are not too big. Live plants may get eaten so you may want to consider plastic. They will stuff themselves under live plants as well.
If you do wish to put more than one crayfish in a tank, be sure there are plenty of hiding places that they can back into and defend themselves. Watch for any about to molt. They will be the ones you either need to move to another tank until they get hard again or have a place that they can hide completely. There is a good chance with too many in the tank, they will do more hiding and you will see less of them.
The crayfish posted in the pictures here is in a temporary tank. He is just big enough for a 10 gallon tank but for a few weeks I have him in a 2 gallon. He has plenty of filtration to keep him happy though. (I have since moved him to his own 10 gallon tank.)
Caution: Be sure you do not accidentally expose your air pump to hazardous chemicals like bug spray. Click here for my close call.
Temperature: I have read that you do not need a heater and other places suggest the range of temperature for a tropical fish. The warmer it is, the faster they grow but do not get it above 80-85 degrees F or so. I keep mine around 75-78 degrees F. Basically it depends on the species you have. Some need cooler temps (around 60-65 F) than others. If you are unsure, go with house temp until you can find out. Do not count on the pet shop to be sure. Sorry this one is not much help.
Molting: A crayfish grows by shedding its outer exoskeleton or carapace when they outgrow it. The carapace tends to stay intact and will look like you have a dead crayfish or have suddenly sprouted another one. If the shell is hollow, then your crayfish has simply molted.
The picture to the right shows a molt laying on its back. You can see the legs sticking up and the tail towards you. It is pale because it has been sitting for over a day (and no one is inside). His mouth parts just got hard enough to eat it and it was mostly gone later in the day after taking this picture. I will remove what he does not eat tonight.
After molting, the crayfish soft for awhile. Because of this, they tend to stay in hiding when they are going to molt. This is one sign that is is about to happen. When their body is soft, they are vulnerable to anything that wants to eat them (other crayfish). Eventually they will harden (1 or 2 days ?) and go about their normal behavior. It is tempting to take out the carapace and dry it out. It looks neat. But the crayfish benefits greatly if it can eat its old shell.
Because they are at first soft, they cannot eat. Their mouth parts also have to get hard. Do not bother to feed them for a day or two. The shed carapace will sit at first but once you see the little guy eating it, then you can start feeding him again.
The picture to the left shows a molt in the foreground. The tail is facing you and the part at the far right is his back that flipped up. You can see a huge gap between the tail and his back where he backed out of the carapace. The crayfish is recovering a bit in the background. He was shy and eating less for the week leading up to this point. After his parts became hard, he was back to his spunky, threatening everything that walks by, self.
**Click here to see more molt pictures and to read about what you can do with a molt. Do remember that the crayfish should be allowed to eat most of its molts.***
If you catch them molting it is fascinating. You will notice at first the crayfish does not seem to fit well within his shell. He is pumping himself with water to expand his body so he can split the carapace. You may also notice that his eyes look dull. Sometimes you do not see this but his behavior will change. He will become shy and stop eating for up to a week before the molt. Mine tried to dig a burrow but since the rocks are not deep enough, he dug a long trench. Seemed happy enough. I left him alone during his shy time to reduce stress.
A break will be seen on the dorsal side where the tail joins the body. It is here where the crayfish will back out. It looks like a lot of work. He will eventually slip completely out of his shell. Even part of the lining of his mouth and beyond is shed.
If they were missing an appendage before the molt, you may now see a new limb. They molt more frequently when young and only molt on occasion when adults. Also replacing a limb takes a lot of energy and the crayfish may not get much bigger with the next molt if it needs to grow a limb. The energy it would have used in all over body growth will end up going towards growing that limb back.
Molting may take some time to finish. You may catch them half in and half out and it will look wierd. If you have them in a tank without substrate (just glass bottom) they may have some difficulty snagging the molt to get it off. Sometimes a molt can just go bad and result in death. If you have them on a healthy diet and good water, then you should be OK. One questions I have been asked is whether they sleep on their back. Healthy crayfish do not sleep on their back. If yours is doing this then it is sick, trying to molt, or having a bad molt. If you see what looks like feathers on their sides after a molt, then the molt has definitely gone bad. Those are its gills and they should be inside of its body.
Lost limbs: Do not worry if your crayfish loses a limb. They can grow back-especially if they have a good diet and water conditions. It depends when the crayfish had lost its part on whether you will see the new limb with the next molt. If a long time before a molt, you will have a chance to get a replacement limb by the next molt. If near molting, you may not get a new limb until a later molt or the new one may be smaller than the others this time around. They should eventually become normal size after later molts. The new limb grows squished up under the carapace and is freed when the crayfish molts. If a claw is lost, they will be mismatched for some time.
Here he is threatening the camera. He came out just to do that. Cute!
Personality: They are spunky. My little male will come up to the side of the tank and display his claws when he sees me (unless about to molt). The males tend to be a bit more aggressive but both sexes are pretty spunky. They will go after about anything. I do not suggest holding them.
They are most active at night but will adjust to your schedule some. They will either sit and wait for something to come by that they can catch or they will wander around the tank digging through the rocks and accessories looking for food. You can see them feeling around with their antenna. The smaller set of antennae are more sensitive to smell/taste. If I remember right, they can also smell/taste a little with their feet. When they find something they like they will rapidly snag it and bring it right up to their mouth to start eating.
They will use their legs to clean their body. Sometimes you will see a leg reaching places you would not think possible.
In the wild they tend to hide a lot but they usually are less shy after awhile in a tank.
Breeding: They breed easy. . I have not bred any myself. The females will carry the eggs under the tale (with berry). Here is a link on breeding http://www.aquaticcommunity.com/inv/breedingcrayfish.php. I will add more later.
Choosing: If you have a choice out of several, try to go for one that is not too shy and has all of its limbs. I prefer to get smaller ones so I can watch them grow and have them longer. A really large one may be old, though they look impressive. But the big ones are good breeders if you are wanting to breed crayfish. Or you can just catch one outside if you have them around you. Watch for parasites.
Also watch for parasites. Many will have what looks like tiny worms attached to the soft areas between joints are under the tail. A few of these are OK. They are supposed to be harmless though they are not fun to look at. Do not try to medicate for them. Fish meds will kill the crayfish. You can pick off these “worms” or remove a molt to reduce them. They will be back though.
Other things to watch for is fuzzy, growth on the carapace or holes in the carapace. They can also carry ick. It is hard to treat invertebrates for diseases in the same way you would fish. So be choosy.
I found mine at a local pet shop that had a large fish section. At least here in Florida, most of these pet shops carry them. The smaller chains seem to have them more than the large, pet supply type stores. Otherwise you can order them online. The shipping is high though since they have to be over-nighted. I do not know if they are allowed out of the US or not. I guess it depends where you are and what regulations there are on importing exotics.
Links and sources (that are not already listed in the blog above):
http://www.anapsid.org/crayfish.html Has a useful short blurb on caring for crayfish as well as good links at the end.
http://aqualandpetsplus.com/Live%20Food,%20Crayfish.htm Pictures! Not a lot of information but this site has some great pictures of various species of crayfish. Definitely check this one out.
Here are two sites with FAQs and additional links that are useful http://crayfish.byu.edu/faq.htm and http://www.wetwebmedia.com/FWSubWebindex/crayfishdisfaq.htm There are even sections about diseases.
Here is a great pdf to dowload by JBL on freshwater crustacea. It is a big file for those of you on dial up. http://www.jbl.de/dl_documents/uk/uk_WWW9.pdf. It is geared towards selling their product but there is useful information in it and great pictures.
I think it may be available in other languages as well. See www.jbl.de and click on the flag that fits your language.
More to come, I have my links scattered between computers. (sigh)…
In the mean time, for more fish and tank related stuff, go to my Categories listed on the right and click on fish from the drop down menu. (Hopefully it will show all.)
He is checking out his reflection here. When he gets to his big tank (he is there now) I will put a background in that is not blue so he stands out more.
It is not decorated yet and I am not sure I like the dark rocks. But they were there already.
Molts since I have had him (hopefully I remember):
1. September 2008
2. Early November: He molted again!
3. March 08, 2009. He is getting to be a big boy! He had a long down time of not eating and hiding more than usual before this molt. I was worried. Looks good now.
4. March 26, 2009. Already another molt!! He has really grown! Also grew back a broken antenna with this molt. I am trying to set this molt so click here to see how it goes. Should be up soon.
Feb 1, 2010. Still not molt. Long stretch this time between.
5. Feb. 5, 2010. Ha! It is like he heard me. He has molted. The ghost shrimp are munching on it. Iwill pull it out in the morning. I am not going to preserve this one except for maybe a claw.
6. March 3, 2010. Another molt already! He is looking so blue! (in a good way)
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